Prognostic Value of Spatial Trajectory of J-Point Amplitude Across Left Precordial Leads in a Community-Based Population.

INTRODUCTION: Early repolarization has historically been regarded as benign in many settings, although specific J-point features have been linked to adverse outcomes. Whether spatial variation in J-point amplitude across adjacent precordial leads carries prognostic information remains unclear. METHODS: This retrospective cohort study included participants aged 40-90 years without self-reported myocardial infarction or heart failure from the Third National Health and Nutrition Examination Survey (NHANES-III). Latent class trajectory analysis was used to identify spatial trajectories of J-point amplitude across leads V4-V6. The primary outcomes were all-cause mortality and cardiac death. Cox proportional hazards regression and competing risk models were used to evaluate associations between J-point trajectory patterns and outcomes. RESULTS: Among 5696 eligible participants, the mean age was 57.6 ± 12.9 years, 3092 were women, and 3986 were non-Hispanic White. LCTA identified two spatial trajectories: Class 1 included 5295 participants and showed a low, mildly decreasing amplitude pattern, whereas Class 2 included 401 participants and showed higher V4 amplitude with a steeper decline toward V5-V6. During a median follow-up of 303 months, all-cause deaths occurred in 2935 and 257 participants, with 790 and 87 cardiac deaths, respectively. In fully adjusted models, Class 2 was associated with higher risks of all-cause mortality (HR, 1.20; 95% CI, 1.03-1.39) and cardiac death (HR, 1.31; 95% CI, 1.01-1.71). CONCLUSION: A steep V4-to-V6 decline in J-point amplitude was associated with increased long-term all-cause and cardiac mortality. This spatial ECG phenotype may capture prognostic information beyond conventional early repolarization criteria and warrants external validation.